It is known to provide intravenous (IV) drug and fluid delivery systems that include a primary line connected to a bag of saline or other fluids, and a branch or auxiliary line connectable to supplies of drugs or other treatment fluids. The branch line and main line are connected at a Y-connector. A check valve is provided in the main line to prevent backflow of the secondary fluid into the main fluid bag. When a drug is dispensed, the backflow pressure on the check valve closes the valve to prevent backflow of the drug into the saline or other non-drug bag. When a drug or other fluid is not dispensed from the auxiliary line, saline flows freely through the check valve.
A known check valve for this purpose is taught by U.S. Pat. No. 4,765,372 hereby incorporated by reference. The valve disclosed therein includes a housing, a biasable diaphragm within the housing and a valve seat carried by the housing against which the diaphragm is urgeable. The housing has a fluid inlet and a fluid outlet. The diaphragm is preferably disposed transverse to a preselected direction of fluid flow through the housing for controlling fluid flow therethrough. The diaphragm can be urged against the seat for preventing fluid from flowing contrary to the preselected direction of flow. The housing engages opposite sides of the diaphragm so that areas of the diaphragm can be moved away from and toward the valve seat without the diaphragm being displaced from its operative position within the valve.
While valves of the type described have worked successfully, contaminants in the system can interfere with proper operation. If a contaminant particle embeds itself in the diaphragm or seal surface, a proper seal may not be provided. The particle may prop open the diaphragm, in which case a drug dispensed from the secondary path may backflow through the check valve, thereby preventing the patient from receiving the proper drug dosage concentration or timely delivery of the drug.
Contaminants can be created during the manufacture and assembly of IV sets. Particles from many sources can migrate and be trapped in the IV set, and later be carried by fluids into the check valve. The sources of contaminant particles include and are byproducts of handling, processing and migration of other materials that work their way into the IV set system. For example, it is known to cut tubes and assemble bag spike components to enable attachment to associated devices. Cutting or puncturing the tube can generate tubing debris that can compromise the sealing function if the particles migrate to the check valve. Other particles from the environment also can be trapped in the IV set and be carried to the check valve.
PCT patent application WO 2010/107597, hereby incorporated by reference and assigned to the assignee of the present invention, describes a check valve having an integrated screen to trap contaminant particles away from a sealing area of the check valve.